92. Reverse Linked List II - LeetCode

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* reverseBetween(ListNode* head, int m, int n) {
        vector<ListNode*> revers;

        ListNode* node;
        ListNode* start = node;
        int i = 0;


        while (head){
            i++;
            if (i >= m && i < n) {
                revers.push_back(head);
                head = head->next;
            }else if (i == n && !revers.empty()) {
                revers.push_back(head);
                reverse(revers.begin(), revers.end());
                for (auto a : revers) {
                    node->next = a;
                    node = node->next;
                }
                head = head->next;
            }else {
                node->next = head;
                node = node->next;
                head = head->next;
            }
        }
        return start->next;
    }
};